Throughout the play Becky Shaw, characters travel between Boston, Providence, New York, and Richmond. That seems plausible, but to look around at the audience in Round House Theatre one night last week, you would have thought travel between Bethesda and say, Columbia Heights, is impossible.

Which is to say, it’s a shame the theater was half-filled with septuagenarians rather than spilling over with 20- and 30-somethings. The target audience for this biting comedy is anyone who has ever been tempted to select the “It’s complicated” relationship-status option on Facebook. That’s what, half of under-50 Washington? So it seems relevant to point out that Bethesda is just a Metro ride away. It’s worth the trip to check out the best play about trainwreck relationships you may ever see.

Will Gartshore, better known around town as a song-and-dance man, makes a fantastic straight-play star turn as Max, the adopted son of a recently deceased well-to-do Richmond businessman. Now a successful financial adviser, Max summons his adopted mother Susan and sister Suzanna to New York to sort out the family’s finances, and he brings bad news.

But it’s sex, not money, that’s the root of all evil in this play, or at least a serious complicating factor. Susan (Brigid Cleary) has taken up with a young gold digger named Lester, which angers Suzanna (Alyssa Wilmoth Keegan), who desperately misses her father. Max urges her to stop wallowing, and somewhat impulsively, she marries Andrew (Rex Daugherty), a fellow grad student from Brown. She’s a psychology Ph.D. candidate who needs therapy; he’s the sensitive MFA type. They’re a match, though perhaps not for long.

Daniel Conway designed the turntable sets, which seamlessly rotate from a Manhattan hotel room to Suzanna and Andrew’s Providence two-bedroom. Andrew isn’t quite sure what to make of Max, who didn’t join the family until age 10. In a well-meaning effort to smooth things out, the newlyweds talk him into to going on a double date with a temp in Andrew’s office named Becky Shaw, who is played by Michelle Six with hard-to-read nuance.

In literature, Rebeccas tend to be devious, amoral females. There’s the conniving Becky Sharp of Vanity Fair and the titular character in du Maurier’s novel Rebecca, who traumatizes people from beyond the grave. Playwright Gina Gionfriddo has not used the name lightly. Becky Shaw is trouble from when she first walks in, but the extent to which she intentionally becomes a caustic catalyst is a major element of tension in this disturbingly funny play.

“You look like a birthday cake,” Max announces, sizing up Becky’s fitted hot pink lace dress, oversized necklace, and decorative headband that’s nearly a fascinator.

The date does not go well. Max is not a terribly sensitive guy—“He’s emotionally crippled,” is Suzanna’s assessment. But she disagrees with her husband’s pronouncement that Max is an all-around asshole. “Goodness,” he tells her, “is not the same thing as being nice to Suzanna.”

The entire script crackles with wit and aphorisms. (In 2009, it was a Pulitzer Prize finalist.) This is the sort of play that has you laughing in the seats and sends you home unable to sleep. The circumstances that these characters face may seem extreme, but individually, Max, Suzanna, and Andrew are all too real. They are the sort of people you are drawn to date or sleep with—and you regret it. The thrill of Becky Shaw is akin to watching videos of last month’s CSX explosion outside of Baltimore: You know you’re watching a stunning disaster, but you also know you’ll survive it.